Buggy code:
public class UtilityService implements Service { private transient Service parent ; private ServiceStats stats ; private ServiceSubscriptionState subscriptions ; public UtilityService ( ) { } public UtilityService setParent ( Service parent ) { } @ Override public void authorizeRequest ( Operation op ) { } @ Override public void handleRequest ( Operation op ) { } @ Override public void handleCreate ( Operation post ) { } @ Override public void handleStart ( Operation startPost ) { } @ Override public void handleStop ( Operation op ) { } @ Override public void handleRequest ( Operation op , OperationProcessingStage opProcessingStage ) { } private void handleAvailableRequest ( Operation op ) { } private void handleSubscriptionsRequest ( Operation op ) { } public void notifySubscribers ( Operation op ) { try { <START_BUG> if ( ( this . subscriptions ) == null ) { <END_BUG> return ; } if ( ( op . getAction ( ) ) == ( Action . GET ) ) { return ; } long now = Utils . getNowMicrosUtc ( ) ; Operation clone = op . clone ( ) ; clone . addPragmaDirective ( PRAGMA_DIRECTIVE_NOTIFICATION ) ; for ( Map . Entry < URI , ServiceSubscriber > e : this . subscriptions . subscribers . entrySet ( ) ) { ServiceSubscriber s = e . getValue ( ) ; notifySubscriber ( now , clone , s ) ; } if ( ! ( performSubscriptionsMaintenance ( now ) ) ) { return ; } } catch ( Throwable e ) { this . parent . getHost ( ) . log ( Level . WARNING , "Uncaught<seq2seq4repair_space>exception<seq2seq4repair_space>notifying<seq2seq4repair_space>subscribers<seq2seq4repair_space>for<seq2seq4repair_space>%s:<seq2seq4repair_space>%s" , this . parent . getSelfLink ( ) , Utils . toString ( e ) ) ; } } private void notifySubscriber ( long now , Operation clone , ServiceSubscriber s ) { } private boolean performSubscriptionsMaintenance ( long now ) { } private void handleUiRequest ( Operation op ) { } public void redirectGetToHtmlUiResource ( Operation op , String htmlResourcePath ) throws UnsupportedEncodingException { } private void redirectGetToTrailingSlash ( Operation op , String folderPath ) throws UnsupportedEncodingException { } public void proxyGetToCustomHtmlUiResource ( Operation op , String htmlResourcePath ) { } private void handleStatsRequest ( Operation op ) { } private ServiceStats populateDocumentProperties ( ServiceStats stats ) { } private void handleDocumentTemplateRequest ( Operation op ) { } @ Override public void handleConfigurationRequest ( Operation op ) { } public void handlePatchConfiguration ( Operation op , ServiceConfigUpdateRequest updateBody ) { } @ Override public void setStat ( ServiceStat stat , double newValue ) { } @ Override public void adjustStat ( ServiceStat stat , double delta ) { } @ Override public ServiceStat getStat ( String name ) { } private ServiceStat getStat ( String name , boolean create ) { } private void replaceSingleStat ( ServiceStat stat ) { } private void replaceAllStats ( ServiceStats newStats ) { } private ServiceStat findStat ( String name , boolean create ) { } private void allocateStats ( ) { } private synchronized boolean allocateStats ( boolean mustAllocate ) { } @ Override public ServiceHost getHost ( ) { } @ Override public String getSelfLink ( ) { } @ Override public URI getUri ( ) { } @ Override public OperationProcessingChain getOperationProcessingChain ( ) { } @ Override public ProcessingStage getProcessingStage ( ) { } @ Override public EnumSet < ServiceOption > getOptions ( ) { } @ Override public boolean hasOption ( ServiceOption cap ) { } @ Override public void toggleOption ( ServiceOption cap , boolean enable ) { } @ Override public void adjustStat ( String name , double delta ) { } @ Override public void setStat ( String name , double newValue ) { } @ Override public void handleMaintenance ( Operation post ) { } @ Override public void setHost ( ServiceHost serviceHost ) { } @ Override public void setSelfLink ( String path ) { } @ Override public void setOperationProcessingChain ( OperationProcessingChain opProcessingChain ) { } @ Override public void setProcessingStage ( ProcessingStage initialized ) { } @ Override public ServiceDocument setInitialState ( String jsonState , Long initialVersion ) { } @ Override public Service getUtilityService ( String uriPath ) { } @ Override public boolean queueRequest ( Operation op ) { } @ Override public void sendRequest ( Operation op ) { } @ Override public ServiceDocument getDocumentTemplate ( ) { } @ Override public void setPeerNodeSelectorPath ( String uriPath ) { } @ Override public String getPeerNodeSelectorPath ( ) { } @ Override public void setState ( Operation op , ServiceDocument newState ) { } @ SuppressWarnings ( "unchecked" ) @ Override public < T extends ServiceDocument > T getState ( Operation op ) { } @ Override public void setMaintenanceIntervalMicros ( long micros ) { } @ Override public long getMaintenanceIntervalMicros ( ) { } @ Override public Operation dequeueRequest ( ) { } @ Override public Class < ? extends ServiceDocument > getStateType ( ) { } }

Fix:
if ( ( ( this . subscriptions ) == null ) || ( ( this . subscriptions . subscribers ) == null ) ) {